Compressor

ABSTRACT

A compressor for providing pressurized air at a predetermined pressure and at a predetermined volume. The compressor has a motor with a shaft to which an eccentric is attached which moves a crank rod upwardly and downwardly and to which is attached a flexible diaphragm. The reciprocal movement of the diaphragm draws air into a chamber while an inlet flapper valve opens and expels air from the chamber through an outlet flapper valve. The flapper valves are made from spring steel and act in a cantilever movement to open and close the inlet and outlet passageways. O-rings are provided to deaden the sound of the flappers. A counterweight is attached to the eccentric to provide an opposed force to the force generated by rotation of the eccentric. An air bleeder allowing air movement between the inlet and outlet passageways may be provided to adjust the air pressure emanating from the compressor.

INTRODUCTION

This invention relates to a compressor and, more particularly, to a diaphragm compressor used generally with a diesel heater and which compressor is used to provide the necessary air under pressure in order to draw fuel into an atomizing fuel nozzle.

BACKGROUND OF THE INVENTION

Powered heaters which use diesel fuel can take many different forms. The present heater with which the compressor is used is a powered heater with an atomizing type nozzle. The use of air under pressure when introduced to the nozzle creates a negative pressure or suction which draws fuel into the nozzle which fuel is then mixed with the air and forms a cone shaped spray emanating from the nozzle with fine particles of fuel. The spray is ignited by a flame rod which is electronically activated.

The compressor is important in such a vaporizing type burner. Any variation of the pressure from the compressor affects the spray pattern and, hence, the combustion characteristics of the burner which, in turn, will adversely will affect BTU output and the emission output from the burner or any heater within which it is positioned. The compressor must not only maintain appropriate characteristics throughout a range of operation but it also must be robust for long life. Its operating characteristics must remain consistent over the life of the compressor and this is particularly so for military operations which use such a burner.

Previously, compressors have been used with various problems arising. One problem is that the valves on such compressors are usually made from a petroleum based material. Upon exposure to diesel laden fumes from the heater, the valves are adversely affected which lowers the life of the valves and, during the period before failure of the valves and adversely affects the operating profile of the compressor. A further problem with existing compressors is that the motors which power the piston and diaphragm are susceptible to overheating due to long hours of compressor use. The overheating is passed to the valve material which adversely affects the valve operation and may cause premature failure. Yet a further motor problem is that the compressor starts and stops many thousands of times with the heater being turned off and on to effect the heating of coolant used both for space heating and for heating potable water for use in showers and the like. If the motor does not have sufficient robustness, flat spots will occur between the brushes and the windings which will prevent the compressor from being operated. Yet a further problem lies in the interface between the valves and the compressor head where the valves alternatively open and close. It is important that this interface maintain integrity in both the open and closed positions to properly maintain the pressure from the compressor when the valves are open and to allow the pressure to be reduced when the valve is closed. Previously, due to heat on the compressor head, the interface could deform thus adversely affecting the seal between the valve and the seat. Adversely affecting this seat adversely affects the characteristics of air emanating from the compressor. Yet a further problem with existing compressors is that they are specifically designed for maintaining specific pressure. If a different pressure is required, the compressor must be replaced or substantially modified.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided a compressor used for supplying air to a nozzle, said compressor comprising a motor with an extending shaft to power said compressor, an eccentric crank connected to said shaft, a crank rod connected to said eccentric crank, a counterbalance connected to said eccentric crank and used to offset the force generated by the rotation of said crank rod and said eccentric crank, a body portion within which said crank rod moves and which includes a body head, a valve head portion housing inlet and outlet openings with flapper valves allowing the opening and closing of said inlet and outlet openings, a spacer portion having inlet and outlet passageways allowing egress and ingress of air moving through said inlet and outlet openings, a diaphragm between said body head and spacer portions which diaphragm is moved upwardly and downwardly by said crank rod, a seal between said valve head and spacer portions and first and second generally flat flappers opening and closing said inlet and outlet passageways, one of said flappers being connected to said valve head portion and the other of said flappers being connected to said spacer portion.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Specific embodiments of the invention will now be described, by way of example only, with the use of drawings in which:

FIG. 1 is a diagrammatic isometric view of the compressor and motor according to the invention in its closed position and further illustrating the inlet port with air filter fitting attached to the head;

FIGS. 2A and 2B are diagrammatic isometric and side views of the compressor of FIG. 1 particularly illustrating the counterweight connected to the motor shaft and the plug closing the opening in the body of the compressor;

FIG. 3 is a diagrammatic isometric view particularly illustrating the head of the compressor and the components within in head;

FIG. 4 is a diagrammatic isometric view of the compressor particularly illustrating the flapper valve of the compressor used for the outlet;

FIG. 5 is a diagrammatic cutaway view of the compressor illustrating its principal components as well as the crank rod connected to the eccentric; and

FIG. 6 is a diagrammatic schematic view of the operating components of a diesel fueled air aspirated burner which includes the compressor according to the invention.

DESCRIPTION OF SPECIFIC EMBODIMENT

Referring now to the drawings, a burner is generally illustrated at 100 in FIG. 6. The components that are included in such a burner 100 include a nozzle 101 to disperse the air and fuel, a fuel solenoid 102 used to prevent fuel flow back from the nozzle 101, a fuel regulator 103 known as a zero pressure regulator, a fuel pump 104 used to pump fuel from the fuel supply (not illustrated) to the zero pressure regulator 103 and thence to the nozzle 101 and a fuel filter 110 to filter the diesel fuel coming from the fuel supply (not illustrated). A combustion fan 111 draws ambient air into the burner 100 and provides this air into the combustion chamber shown generally at 112. The air provided by the combustion fan 111 is intended to create a forced air flow through the combustion chamber 112 so as to provide optimal combustion for the air and fuel. An igniter 113 is provided to provide an infrared glow so as to ignite the fuel-air mixture emanating from nozzle 101.

A compressor 120 is operably mounted so as to provide a constant air supply to the nozzle 101 at a specific and predetermined pressure and flow rate. A filter 121 filters the ambient air before it enters the compressor 120.

Referring now to the compressor generally illustrated at 120 in FIG. 1, a motor 122 is connected to the body portion 123 of compressor 120 with screws or bolts 124 (FIG. 2A). Motor 122 has a shaft 130 (FIG. 2B) protruding from one end. The shaft 130 extends through a bearing 131 (FIG. 5) mounted within a crank rod 132 which reciprocates when the motor 122 is operating. The crank rod 132 has a piston head 133 with a rubber or synthetic flexible diaphragm 134 connected thereto by way of a circular keeper 140 and bolt 141 extending through the keeper 140 and into the piston head 133 to retain the diaphragm 134.

Inlet and outlet passageways 142, 143, respectively, extend through the valve head portion 144, thence through a spacer 150 and into the cavity 151 formed between the spacer 150 and the diaphragm 134. A pair of generally flat flapper valves 152, 153 made from thin spring steel are provided so as to allow air egress and air ingress to the cavity 151. The use of spring steel for the flapper valves 152, 153 allows for a long lasting and diesel resistant operation. Flapper valve 152 is connected to the head portion 144 by a screw or bolt (not illustrated) so as to move in a cantilever type motion and opens and closes the outlet passageway 143. Flapper valve 153 is connected to the spacer portion 150 in the same manner and opens and closes the inlet passageway 142. O-rings 154 are provided within machined grooves in the spacer 150 and serve to reduce the noise of the flapper valves 152, 153 as they open and close and also to lend additional effectiveness to the sealing ability of the compressor 120 when the respective flapper valves 152, 153 are in their closed positions.

Spacer 150 is sandwiched upon assembly between valve head portion 144 and body head portion 160. Four bolts 161 (FIG. 1) extend from the head 144, through spacer 150 and diaphragm 134 into the body head portion 160 of body 123 to tightly seal the three components. An o-ring 162 is positioned within a machined groove in spacer 150 and surrounds the outlet passageway 143 in spacer 150 to ensure all air emanating from the outlet passageway 143 in spacer 150 exhausts through outlet passageway 143 and to ensure sealing integrity.

The body 123 has a circular opening 163 machined in one side (FIG. 3) so as to allow access to the interior of the body 123 for assembly and servicing operations. A removable rubber plug 164 (FIG. 1) is used to close the opening 163 after assembly to prevent the ingress of contamination though the opening 163. To service or inspect the components within the body 124, the plug 164 is manually removed.

A counterweight 170 (FIG. 3) is connected to the shaft 171 of the eccentric 172 (FIG. 5). The counterweight 170 operates to offset the force created by the rotation of the eccentric 172.

Air filter 121 (FIG. 3) is provided to filter the air entering into the inlet passageway 142 of compressor 120.

Fins 173 are provided on the outside of the valve head 144 (FIG. 1) to allow better dissipation of the heat buildup which takes place during compression.

Operation

In operation, the power switch (not illustrated) is turned on to provide power to the heater 100 (FIG. 1). The igniter 113 will begin to glow and the combustion fan 111 will remain in the off condition. For a HURRICANE (Trademark) heater manufactured by International Thermal Research Ltd. of Richmond, British Columbia, Canada, the igniter 113 will remain on for a period of approximately ten (10) seconds to allow it to reach ignition temperature.

The air compressor 120, fuel pump 104, fuel solenoid 102 and combustion fan 111 will then be turned on.

The motor 122 of compressor 120 will rotate and the shaft 130 of the motor 122 will rotate the eccentric 172 mounted to the shaft 130 (FIGS. 1 and 5). The shaft 171 of eccentric 172 will provide the reciprocating motion to the crank rod 132 and the crank rod 132 will rotate at the same rpm as the motor 120. Upwardly and downwardly movement is therefore provided to diaphragm 134. As the diaphragm 134 moves downwardly as viewed in FIG. 5, flapper 153 will open as air is drawn into the inlet air passageway 142, through the opening created by the now open flapper valve 153 and into cavity 151 in the spacer 150.

When the diaphragm 134 reaches its most downwardly position and crank rod 132 begins to move upwardly as seen in FIG. 5, flapper 153 will close under the positive pressure in cavity 151 and flapper 152 in outlet passageway 143 will open. Air will therefore exhaust through outlet passageway 143 under a predetermined pressure and at a predetermined flow rate according to the size of the cavity 151, the speed of the motor 122 and the sizes of the inlet and outlet passageways 142, 143.

The air under pressure will leave the outlet passageway 143 and enter the nozzle 101 (FIG. 6). The solenoid 102 will be in the open position to allow fuel to pass from the fuel regulator 103 to the nozzle 101. The compressed air is guided over the tip of the nozzle 101 where a negative pressure is created. The negative pressure will draw fuel from the fuel regulator 103 to the nozzle 101. The nozzle 101 creates a fine cone pattern spray which is ignited by the igniter 113.

Fuel pump 104 pumps fuel to the fuel regulator 103 and a fuel filter 110 is provided to filter the fuel entering into fuel pump 104 from a fuel supply (not illustrated).

The combustion fan 111 draws in outside ambient air which creates a forced air flow through the combustion chamber 112 and to exhaust the combustion gasses through an exhaust system (not illustrated).

When the operation of the burner 100 is terminated, the solenoid 102 is closed to prevent fuel from being drawn from the nozzle 101. This allows a cleaner ignition of the fuel when the burner 100 commences operation.

Many modifications will readily occur to those skilled in the art. For example, the inlet passageway 142 in the valve head 144 (FIG. 5) may be fitted with an air bleeder hole 174 which extends from the outside of the valve head 144 and through the space 180 (FIG. 5) between the air inlet cavity 181 and the air outlet cavity 182 as is illustrated by the broken lines in FIG. 5. A set screw (not illustrated) would be inserted into the air bleeder hole 174 and would allow adjustment of air passing between the inlet air chamber 181 and the outlet air chamber 182. This would allow for the pressure provided to the nozzle 101 by the compressor 120 to be adjusted depending upon the fuel combustion characteristics desired by the specific nozzle 101 that might be used in the heater.

While the compressor 101 is made from aluminum to prevent rusting and to provide lightened weight, it is contemplated that other suitable materials might also be used. For example, stainless steel could be used or the entire compressor 101 could have the components molded in an appropriate synthetic plastic. The use of molded materials could also enhance the sound deadening qualities of the compressor 101 and would reduce costs for large quantities of production.

It is important for the flapper valves 152, 153 to be of the appropriate thickness for the characteristics of the compressor 101. If the thickness of the flapper valves 152, 153 is too great, the cantilever action will be restricted and thereby reduce the air traveling through the inlet and outlet chambers which, in turn, will reduce the pressure emanating from the compressor 101. A thickness for the flapper valves 152, 153 which is too small will result in inadequate sealing strength when the flapper valves are closed or it may result in damage to the flapper valves since they would be too think to accept a certain amount of punishment during operation.

Many further modifications will readily occur to those skilled in the art to which the invention relates and the specific embodiments herein described should be taken as illustrative of the invention only and not as limiting its scope as defined in accordance with the accompanying claims. 

1. A compressor (120) used for supplying air to a nozzle (101), said compressor (120) comprising a motor (122) with an extending shaft (130) to power said compressor (120), an eccentric crank (172) connected to said shaft (130), a crank rod (132) connected to said eccentric crank (172), a counterbalance (170) connected to said eccentric crank (172) and used to offset the force generated by the rotation of said crank rod (132) and said eccentric crank (172), a body portion (123) within which said crank rod (132) moves and which includes a body head (160), a valve head portion (144) housing inlet and outlet openings (142, 143) with flapper valves (152, 153) allowing the opening and closing of said inlet and outlet openings (142, 143), a spacer portion (150) having inlet and outlet passageways allowing egress and ingress of air moving through said inlet and outlet openings (142, 143), a diaphragm (134) between said body head and spacer portions (160, 150) which diaphragm (134) is moved upwardly and downwardly by said crank rod (132), a seal (162) between said valve head and spacer portions (144, 150) and first and second generally flat flappers (152, 153) opening and closing said inlet and outlet passageways, one of said flappers (152, 153) being connected to said valve head portion (144) and the other of said flappers (152, 153) being connected to said spacer portion (150).
 2. A compressor as in claim 1 and further including an air bleeder (174) to increase and/or decrease the air moving between the inlet and outlet chambers (181, 182) of said valve head portion (144).
 3. A compressor as in claim 2 and further comprising at least one o-ring seal (154) between at least one of said flappers (152, 153) and one of said valve head or spacer portions (144, 150). 